CROSS-IMMUNITY IN CALVES AFTER VACCINATION AGAINST TRICHOPHYTOSIS

Calves vaccinated against Trichophyton verrucosum were resistant to ex perimental infection with T. verrucosum strain and T. mentagrophytes s train. Immunization with a vaccine containing T. mentagrophytes produc ed reliable immunity against the homologous strain but failed to confe r a satisfactory degree of protection against the heterologous dermato phyte T. verrucosum. Four out of 12 calves of this group reacted to ch allenge by development of mycotic changes persisting throughout the ob servation period. All non-vaccinated controls inoculated with one or t he other of the two challenge cultures showed a similar clinical pictu re of trichophytosis.